This invention relates to a gunnery training system of the type in which a target projector projects onto a screen an image of a target, and a spot projector projects onto the screen a spot which traces a path which represents the path of the projectile being simulated and which is dependent upon the sensed positions of various controls operated by the trainee.
The spot projector is mounted on servos, or contains servo-controlled mirrors, so that the tracer spot can be moved in accordance with the projectile trajectory. It is required to provide precise simulation of the possible projectile paths. It should be noted that the shot may pass to one side of the target, or if on the correct line may fall short of the target, be a direct hit, or overshoot. When the shot hits the ground or the target it must be extinguished.
If the round overshoots and falls behind the target, for realistic simulation the tracer spot should extinguish, or occult, as it falls behind the target. It would be possible to do this by sensing the instantaneous positions of the servos operating the two projectors and electronically calculating when the tracer spot falls on the area defined by the target. The resultant can then be used to switch off the spot projector.
We have found that the results obtained by this method are unreliable and unrealistic, at least when such occulting is required, due to the inherent tolerances and time lags of the projectors and their servos.